bibliography * The PainScience Bibliography contains plain language summaries of thousands of scientific papers and others sources, like a specialized blog. This page is about a single scientific paper in the bibliography, Stanton 2018.

Illusory resizing of the painful knee is analgesic in symptomatic knee osteoarthritis

PainSci summary of Stanton 2018?This page is one of thousands in the PainScience.com bibliography. It is not a general article: it is focused on a single scientific paper, and it may provide only just enough context for the summary to make sense. Links to other papers and more general information are provided at the bottom of the page, as often as possible.★★★☆☆?3-star ratings are for typical studies with no more (or less) than the usual common problems. Ratings are a highly subjective opinion, and subject to revision at any time. If you think this paper has been incorrectly rated, please let me know.

This nifty proof-of-concept study shows that “visuotactile illusions” can reduce osteoarthritis pain by up to 40%. That’s substantial, and consistent with the important theory that pain is mostly a brain export only loose related to tissue trouble.

And what kind of illusions were these, pray tell? What sorcery reduces arthritic knee pain just by fooling the brain? Two similar illusions, basically using virtual reality goggles to make it look like the knee was either shrinking or stretching. 😜 Whoaa, duuuuude …

original abstract†Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

METHODS: Participants with knee OA underwent eight conditions (order randomised): stretch and shrink visuotactile (congruent) illusions and corresponding visual, tactile and incongruent control conditions. Knee pain intensity (0-100 numerical rating scale; 0 = no pain at all and 100 = worst pain imaginable) was assessed pre- and post-condition. Condition (visuotactile illusion vs control) × Time (pre-/post-condition) repeated measure ANOVAs evaluated the effect on pain. In each participant, the most beneficial illusion was sustained for 3 min and was repeated 10 times (each during two sessions); paired t-tests compared pain at time 0 and 180s (sustained) and between illusion 1 and illusion 10 (repeated).

RESULTS: Visuotactile illusions decreased pain by an average of 7.8 points (95% CI [2.0-13.5]) which corresponds to a 25% reduction in pain, but the tactile only and visual only control conditions did not (Condition × Time interaction: p = 0.028). Visuotactile illusions did not differ from incongruent control conditions where the same visual manipulation occurred, but did differ when only the same tactile input was applied. Sustained illusions prolonged analgesia, but did not increase it. Repeated illusions increased the analgesic effect with an average pain decrease of 20 points (95% CI [6.9-33.1])-corresponding to a 40% pain reduction.

DISCUSSION: Visuotactile illusions are analgesic in people with knee OA. Our results suggest that visual input plays a critical role in pain relief, but that analgesia requires multisensory input. That visual and tactile input is needed for analgesia, supports multisensory modulation processes as a possible explanatory mechanism. Further research exploring the neural underpinnings of these visuotactile illusions is needed. For potential clinical applications, future research using a greater dosage in larger samples is warranted.